Traditional Japanese stones for the game ‘Go’ are typically double-convex and crafted from clamshell (white) and slate (black). The preferred slate, nachiguro stone, originates from Wakayama Prefecture, while the clamshell comes from either the Hamaguri clam (Meretrix lusoria) or the Korean hard clam. However, due to limited availability of these clams in Japan, the stones are frequently made from shells sourced from Mexico.

19c. Japan

Shell - 7 inches max width

stone - 6 inches max width